Electric razor

ABSTRACT

The invention is directed to a dry shaving apparatus with a housing in which an electric drive mechanism is provided having a drive element for the transmission of a driving motion to at least one cutting element reciprocating in directions of movement, and with at least one movably mounted shaving head formed by a shaving head frame in which at least two cooperating cutting elements are provided, wherein the electric drive mechanism is mounted for oscillation in the housing and the shaving head is adapted to be set in oscillation by the oscillatory motions of the electric drive mechanism.

This invention relates to a dry shaving apparatus

A dry shaving apparatus of the type initially referred to is known fromU.S. Pat. No. 2,339,677. The shaving head formed of a shaving head frameand an outer cutter and an inner cutter is arranged on an upper housingsurface of a housing for reciprocating movement transverse to thedirection of movement of an inner cutter driven to oscillate in thelongitudinal direction. To transmit the driving motion to the innercutter on the one hand and to the shaving head on the other hand, adouble eccentric device is provided on the rotary shaft of an electricmotor fixedly disposed in the housing. The masses comprised of shavinghead, inner cutter and double eccentric device which are driven forreciprocating movement in different directions by driving elementsproduce excessive vibrations perceivable to the user because of thedevelopment of loud noise in addition to causing handling discomfort.

A dry shaving apparatus of the type referred to in the foregoing is alsoknown from DE 1 711 665. In all embodiments of this known printedspecification, the drive element of the electric drive mechanism islinked, likewise through transmission elements such as a gear mechanismor a double eccentric device or a double-armed lever, to both the innercutter and the shaving head equipped with an outer cutter, in order toset the inner cutter and, in addition, the complete shaving head inmotion. Considering the masses to be set in motion by the electric drivemechanism of this specification, which include the transmission elementsand the inner cutter and, in addition, the complete shaving headassembly comprised of shaving head frame, outer cutter and inner cutter,the electric motor is required to deliver an increased power outputwhich needs to be taken into account correspondingly in the design ofthe dry shaving apparatus. The masses needing to be accelerated indifferent directions due to the oscillations and to be decelerated aswell, transmit oscillation couples to the housing of the dry shavingapparatus through the electric drive mechanism secured to the housing.This effect is noticeable on the housing in the form of unpleasantvibrations and loud noise under load.

From DE 3 631 120 A1 it is known to use eccentric balance weights todynamically balance in a dry shaving apparatus the masses such aseccentric device, oscillatory bridge structure with coupling element aswell as inner cutter, which are driven to reciprocate by an electricdrive mechanism, that is, an electric motor, in order to suppressundesired vibrations. These balance weights which are associated withthe electric drive mechanism necessarily require an increased poweroutput of the electric drive mechanism, resulting directly in increasedcost of the electric drive mechanism and, in cases where a dry shavingapparatus is equipped with rechargeable storage cells, in an increasedconsumption of stored energy and hence a reduced number of shaves percharge of the storage cells.

It is an object of the present invention to improve upon a dry shavingapparatus of the type identified in the foregoing.

According to the present invention, this object is accomplished in a dryshaving apparatus of the type initially referred to by the featuresindicated in the main claim.

This approach of the present invention affords a plurality ofadvantages. When the electric drive mechanism is started, the electricdrive mechanism is excited to oscillate in opposition to the directionof movement of one or, where applicable, several cutting elements by themasses set in motion by the drive element and also by the frictionoccurring between the cutting elements provided. Because according tothe present invention the electric drive mechanism is mounted foroscillation, this oscillating excitation, which in the hithertoconventional, standard rigid fastening of an electric drive mechanism tothe shaver housing is transmitted from the electric drive mechanism tothe shaver housing where it consequently produces unpleasant vibrationand loud noise, rather than being transmitted to the housing, remainsinitially with the electric drive mechanism, causing it to oscillateabout its axis. The electric drive mechanism hence follows theoscillatory motions forced upon it without significant effect on thehousing of the dry shaving apparatus. This approach effects first amaterial reduction of housing vibration and noise under load that isderivable therefrom. According to the present invention, theseoscillatory motions of the electric drive mechanism are utilizedadvantageously to set the shaving head of the dry shaving apparatus inoscillation. The oscillation of the shaving head and hence the cuttingelement fixed in the shaving head produces a relative motion between theskin and the cutting element. In consequence, tips of hair that arelocated in close proximity to the cutting element and threadedly engagetherebetween only sparingly in the absence of oscillation are then in aposition to penetrate the cutting openings of the cutting element inmajor quantities. In addition, the oscillation of the shaving headoperates to lengthen the effective hair entrance openings in the cuttingelement in the direction of oscillation. The threaded hair is entrainedby the cutting element configured as inner cutter, the cut beingperformed against the edge of the hair entrance opening in the cuttingelement configured as outer cutter. According to the present invention,the outer cutter moves against the inner cutter, thereby shortening thelength of displacement of a hair that has penetrated the hair entranceopening during the cutting operation, whereby the hair is cut to ashorter length. The cutting performance of the dry shaving apparatus isthus significantly improved. Moreover, on account of the highoscillation frequency of the shaving head, a reduced sliding friction ofthe cutting element becomes effective on the skin.

An essential advantage of the present invention resides in that theoscillating excitation originating from the movable masses, rather thanbeing transmitted to the housing of the dry shaving apparatus as isknown from DE-GM 1 711 665, is transmitted, via the oscillatory mountingof the electric drive mechanism, to the movable shaving head. Hence theenergy of the oscillating excitation is routed from a location in thehousing where disturbing effects occur to a location where this energycan be put to use in advantageous manner. For lack of linkage of itsdrive element with the oscillatory shaving head, the electric drivemechanism is thus not required to supply driving power to this shavinghead.

In a further configuration of this invention, provision is made for atleast the shaving head and the electric drive mechanism to be mountedfor oscillation as an oscillating mass about a common axis ofoscillation.

To compute the position of the axis of oscillation for the electricdrive mechanism in the housing, allowance must be made for the fact thatthe oscillating mass is formed by incorporating the oscillating mass ofthe electric drive mechanism as well as all components adapted to be setin oscillation by the oscillatory motions of the electric drivemechanism, such components including, for example, the shaving head,support arms for the shaving head and/or bearing cage for the electricdrive mechanism and/or an oscillatory bridge structure for an additionalcutting unit or by fitting additional oscillating masses.

In a preferred embodiment of the present invention, the electric drivemechanism is mounted for oscillation about an axis of oscillation.

A preferred embodiment of the present invention is characterized in thatthe shaving head is mounted for oscillation in the housing by means ofat least one oscillating element.

In a preferred embodiment of the present invention, the oscillatingelement is formed by support arms having joints.

In another embodiment of the present invention, the oscillating elementis formed by a housing portion.

A substantial improvement of the cutting performance of the cuttingelements and an appreciable reduction in vibration of the housing of thedry shaving apparatus are obtainable by arranging the axis ofoscillation so as to extend through the center of impact of theoscillating mass. The center of impact of the oscillating mass is thelocation about which the motor would oscillate if a drive unit—comprisedof electric drive mechanism and driven elements—operating at rated speedwere able to oscillate freely. At this location the bearing forces to beexerted for the oscillating mass, which in this case is the drive unit,reach their minimum, causing undesired housing vibration to be reducedto a minimum.

According to another embodiment of the present invention, the axis ofoscillation is provided at a distance to the center of impact of theoscillating mass. With such an approach it is possible to vary, forexample, the extent of the oscillation amplitude of the electric drivemechanism and hence of the shaving head linked thereto in simple manner.

In a preferred embodiment of the present invention, the shaving head isdrivable by the oscillatory motions of the electric drive mechanism inthe directions of movement A and B of the drivable cutting element. In afurther aspect of this embodiment, provision is made for the shavinghead to be driven by the electric drive mechanism so as to oscillate inopposition to the reciprocating movements of the cutting element. Thisapproach results in an improved cutting performance by reducing the hairdisplacement travel in the hair entrance openings of the outer cutter.

According to the present invention, the cutting performance of thecutting elements is improved by providing for different oscillationamplitudes for the shaving head and the movable cutting element. Thisapproach ensures, for example, an optimum configuration and adaptationof movable cutting elements relative to stationary cutting elements,incorporating the wide variety of geometries of hair entrance openingsin cutting elements operating as outer cutter. The invention furtheraffords a substantial advantage in that the oscillation amplitudes ofthe shaving head and/or the cutting element are variable. The respectiveoscillation amplitudes can be varied, for example, by varying the massesadapted to be set in oscillation, or by relocating the axis ofoscillation away from the center of impact of the oscillating mass.

In a preferred embodiment of the present invention, provision is madefor the oscillation amplitude to be determinable by the cutting elementand for the oscillation amplitude of the shaving head to be adjustablethereto. This approach ensures an optimum relative adjustment ofcooperating cutting elements. Tests performed on a dry shaving apparatusof the present invention revealed that the reciprocating travel of theshaving head in each direction of movement A and B should be provided ina range from 0.05 mm to 1 mm. In a preferred embodiment of the presentinvention, the reciprocating travel of the shaving head should be in arange from 0.15 mm to 0.5 mm. An optimum magnitude of the reciprocatingtravel of the shaving head for a particular type of dry shavingapparatus should be determined on a case-by-case basis, taking intoaccount the respective configuration of cooperating cutting elements, inparticular the hair entrance opening geometries.

In another aspect of the present invention, the electric drive mechanismis mounted for oscillation about the axis of oscillation by means ofpivot bearings. These pivot bearings operate to largely decouple theelectric drive mechanism from the unavoidable housing vibration inaddition to ensuring at the same time that this vibration energy isutilized to advantage to cause an oscillatory motion of the shavinghead. By means of these low-friction pivot bearings the electric drivemechanism is mounted for oscillation in the housing of the dry shavingapparatus, such that it follows the oscillation forced upon the electricdrive mechanism without appreciable reaction on the housing.

An embodiment of the present invention affording ease and economy ofmanufacture is characterized in that the pivot bearing is provided on atleast one support element of the housing and on a housing portion of theelectric drive mechanism. In another advantageous embodiment of thepresent invention, provision is made for the housing portion of theelectric drive mechanism to be securable in a bearing cage.

According to an embodiment of the present invention, provision is madefor the axis of oscillation to be aligned in a direction transverse tothe directions of movement A and B of the cutting element. In apreferred embodiment of the present invention, the pivot bearing for theelectric drive mechanism is configured as a conical bearing.

To make sure that the shaving head performs an oscillatory motion in thedirections of movement A and B, a preferred embodiment of the presentinvention makes provision for at least one support arm for the shavinghead. In a further aspect of this embodiment, at least two joints areprovided on the support arm. For the purpose of transmitting theoscillatory motion forced upon the electric drive mechanism to theshaving head, this embodiment makes provision for at least one supportarm to be adapted to be linked to the electric drive mechanism throughan oscillating element having joints. These joints may be formed, forexample, by joint bolts—not shown—slidably received in bores. Accordingto an embodiment affording low cost manufacture of joints, at least onejoint is configured as a film hinge.

In an advantageous embodiment of the present invention, provision ismade for the support arm to be linked through one joint to at least onesupport element, and through another joint to the shaving head frame ofthe shaving head, such as to be capable of oscillating in the directionsof movement A and B. This embodiment corresponds to a mechanism referredto as a four-bar mechanism. In another embodiment of the presentinvention, the joint for the support arm is provided in the housing atthe housing end opposite the shaving head. This embodiment makes use ofthe available length of the housing of the dry shaving apparatus toaccommodate the length of the support arm, whereby the verticalcomponent derivable from the oscillatory motion is reduced in magnitudeto a minimum, so that a nearly linear oscillatory motion is accomplishedin the directions of movement A and B of the shaving head.

A further very advantageous embodiment of the present invention ischaracterized in that the support arm is linked for oscillation to atleast one support element at the one end and to a supporting framecarrying the shaving head at the other end. In this embodiment, thesupporting frame is adapted to be linked to the electric drive mechanismdirectly, and this through a housing portion of the electric drivemechanism or through a bearing cage encompassing it. In a further aspectof this embodiment, provision is made for the electric drive mechanismto be adapted to be linked to the supporting frame through a housingportion and an engaging device. A simple and low cost embodiment for thetransmission of motion from the electric drive mechanism or a housingportion of the electric drive mechanism to the supporting frame ischaracterized in that the engaging device is formed of a slot and a pinengageable in said slot.

In a further embodiment of the present invention, provision is made forthe drive element of the electric drive mechanism to be adapted to belinked through an oscillatory bridge structure to a cutting element ofthe shaving head. In a still further embodiment of the presentinvention, the drive element of the electric drive mechanism is adaptedto be linked through at least one eccentric device to a cutting elementof the shaving head. Another embodiment of the present invention ischaracterized in that the drive element of the electric drive mechanismis adapted to be linked through an eccentric device configured as adouble eccentric device to cutting elements of different configurations.Cutting elements of different configurations are understood to mean thecutting elements of a short-hair cutter—see FIG. 1—and the cuttingelements of a long-hair trimmer as well. The long-hair trimmer may beprovided on or in the housing of the dry shaving apparatus or in ashaving head in known manner (not shown).

In a further aspect of the present invention, provision is made for theeccentric member of a double eccentric device to be adapted to be linkedto a cutting element of a long-hair trimmer through an oscillatorybridge structure. In a preferred embodiment of the present invention,the electric drive mechanism is configured as a direct-current motorhaving a drive element provided for rotation. An alternative embodimentis characterized in that the electric drive mechanism is configured as arocking armature motor having an oscillatory drive element.

In another embodiment of the present invention, provision is made forthe electric drive mechanism and the shaving head to be held in amid-position by means of a spring element. In a further aspect of thisembodiment, the spring elements bear with one end against the electricdrive mechanism and with their other end against the housing.

Embodiments of the present invention will be described in more detail inthe following with reference to the accompanying drawings. In thedrawings,

FIG. 1 is a longitudinal sectional view of the upper part of a housingof a dry shaving apparatus, with an electric drive mechanism mountedtherein for oscillation, and with a shaving head adapted to be set inoscillation through support arms;

FIG. 2 is a side view of the shaving head of FIG. 1, the housing beingshown in longitudinal sectional view;

FIG. 3 is a longitudinal sectional view of the housing of a dry shavingapparatus and a partial sectional view of the shaving head adapted to beset in oscillation, the shaving head being driven to oscillate by ahousing portion of the electric drive mechanism;

FIG. 4 is a side view of the dry shaving apparatus of FIG. 3, with ashaving head assembly comprised of two shaving heads, the housing beingshown in longitudinal sectional view, and with a support arm mounted inthe housing and on the shaving head;

FIG. 5 is a sectional view of the upper part of a housing, showing anelectric drive mechanism mounted for oscillation in the housing andlinked to the shaving head mounted for oscillation, in which twooscillatory bridge structures are provided; and

FIG. 6 is a sectional view of a part of the housing of a dry shavingapparatus, showing an electric drive mechanism mounted for oscillationin the housing, a double eccentric device for operating two oscillatorybridge structures, and a shaving head mounted for oscillation in thedirections of movement A and B in addition to being mounted for pivotalmovement about the pivot axis Z.

FIG. 1 shows a dry shaving apparatus with a housing 1 in which anelectric drive mechanism 2 is provided having a drive element 3 for thetransmission of a driving motion to at least one cutting element 4adapted to reciprocate in the directions of movement A and B, and with amovably mounted shaving head 6 formed by a shaving head frame 7 in whichtwo cooperating cutting elements 4 and 5 are provided. Arranged in thehousing 1 are two support elements 16 and 17—see FIG. 2—on which theelectric drive mechanism 2 is mounted for oscillation about an axis ofoscillation 8 in a direction parallel to the directions of movement Aand B of the cutting element 4 by means of pivot bearings 12 and 13. Thepivot bearings 12 and 13 are configured as conical bearings.

In addition to the shaving head frame 7 with its cutting elements 4 and5, the shaving head 6 accommodates further components as, for example,an oscillatory bridge structure 25 having a coupling element 30 forcoupling engagement with the cutting element 4, with the requisitecontact pressure of the cutting element 4 against the cutting element 5being ensured by at least one spring element 32 disposed between theoscillatory bridge structure 25 and the cutting element 4. Serving totransmit the driving motion from the drive element 3 to the oscillatorybridge structure 25 is an eccentric device 27 having its one end securedto the drive element 3 while its other end engages by means of a pin ina dovetail-type slot 26 provided on the oscillatory bridge structure 25.

Pivotally mounted on the support elements 16 and 17 by means of joints21 and 22 are two support arms 14 and 15. The ends of the support arms14 and 15 remote from the joints 21 and 22 are connected to end walls 33and 34, respectively, of the shaving head frame 7 by means of joints 23and 24, respectively, in such fashion that an oscillatory to-and-fromotion of the shaving head 6 in the directions of movement A and B ofthe cutting element 4 is ensured. The oscillatory motion of the electricdrive mechanism 2 is transmitted to the shaving head 6 by means of anoscillating element 11 having its one end linked to the support arm 15through a joint 28 and its other end to a housing portion 20 of theelectric drive mechanism 2 through a joint 29. At the end of theelectric drive mechanism 2 remote from the shaving head 6, two springelements 9 and 10 bearing against the housing 1 and acting upon theelectric drive mechanism 2 are provided, said spring elements operatingto hold the electric drive mechanism 2 in a mid-position whendeactivated.

The axis of oscillation 8 passes through the center of impact of alloscillating masses adapted to be set in oscillation when the electricdrive mechanism 2 is started, their moments of inertia being taken intoaccount. These oscillating masses and their moments of inertia differfor each dry shaving apparatus so that the position of the center ofimpact and hence the position of the axis of oscillation 8 need to bedetermined for the particular type of dry shaving apparatus involved,applying physical computation methods well known to the person in theart. Starting from a calculable optimum position of the center of impactor position of the axis of oscillation 8 in the housing 1 of a dryshaving apparatus, bearing arrangements of the axis of oscillation 8that deviate therefrom are possible as well. Due to numerous influencingvariables as, for example, the magnitude of the mass involved and itsmoment of inertia, imbalance of oscillating masses, friction ofcooperating cutting elements, the limits of permissible deviations fromthe optimum center of impact can be determined and fixed for theparticular embodiment only by practical tests in order to thenmanufacture this particular type of shaving apparatus in series.

FIG. 2 shows a longitudinal sectional view of the housing 1 of the dryshaving apparatus of FIG. 1, such that the joints 21 and 23 provided onthe support arm 15 can be viewed. Parallel to the respective axialdirections of the pivot bearings provided, the joints 21 and 23 includebearing trunnions and bearing bores which are disposed in the supportelements 16 and 17 and on the end walls 33, 34 of the shaving head 6.Provided on the support elements 16 and 17 is a respective support wallextending in vertical direction for pivotal connection of the electricdrive mechanism 2 by means of the pivot bearings 12 and 13 configured asconical bearings.

When the dry shaving apparatus is started by turning on the electricdrive mechanism 2, the rotary motion of the drive element 3 of theelectric motor is converted, via the eccentric device 27 and the slot 26provided in the oscillatory bridge structure 25, into an oscillatorymotion of the oscillatory bridge structure 25, this to-and-fro motion ofthe oscillatory bridge structure 25 in the directions of movement A andB being then transmitted through the coupling element 30 to the cuttingelement 4 acting as inner cutter. The cutting element 4 slides along thecutting element 5 configured as a shaving foil in order to cut off hairsthat have entered holes and/or slots in the shaving foil. At the sametime, the electric drive mechanism 2 experiences an oscillatingexcitation in opposition to the respective direction of movement of thecutting element 4 sliding along the cutting element 5. Due to thepivotal mounting of the electric drive mechanism 2, the electric drivemechanism follows the oscillation about the axis of oscillation 8 forcedupon it, with the extent of the oscillation amplitude being lower thanthe extent of the respective oscillation amplitude of the reciprocatingcutting element 4 because of, inter alia, the magnitude and inertia ofthe aggregate of the masses adapted to be set in oscillation. Theoscillation amplitude of the electric drive mechanism 2 is transmittedthrough the oscillating element 11 to the support arm 15 and from thisarm to the shaving head 6, hence setting the shaving head 6 with all thecomponents provided therein in an oscillatory motion going to and-fro inthe directions of movement A and B. Accordingly, the shaving head 6moves in relative opposite directions to the simultaneously movingcutting element 4. The length of travel of the oscillating shaving head6 is substantially shorter than the length of travel of the cuttingelement 4.

FIG. 3 shows a section through the housing 1 of a dry shaving apparatus,with an electric drive mechanism 2 mounted for oscillation about an axisof oscillation 8 on support elements 16, 17 by means of pivot bearings12, 13—see FIG. 4, the mechanism's drive element 3 being connectedthrough an eccentric device 27 to an oscillatory bridge structure 25provided in the shaving head 6 for the purpose of transmitting areciprocating driving motion to a cutting element 4 acting as an innercutter.

The shaving head 6 reciprocating in the directions of movement A and Bis a component part of a four-bar mechanism having links configured assupport arms 14, 15 which are pivotally mounted, by means of joints 21,22, on support elements 46, 47 provided in the housing 1 at the end ofthe housing 1 remote from the shaving head 6. The support arms 14, 15pivotally carried in the joints 21, 22 are passed through openings 48,49 provided in the support elements 16, 17 and are pivotally connectedby means of joints 23, 24 to the end walls 33, 34 of the shaving head 6.The electric drive mechanism 2 includes two housing portions 20, 37.Provided on the housing portion 20 is a pin 43 which is in slidingengagement with a slot 42 provided on the shaving head frame 7 in orderto transmit the oscillating movement of the electric drive mechanism 2through this engaging device 41 to the shaving head 6. By reason of thevery large overall length of the support arms 14 and 15, which length isdetermined by the pivotal connection to the shaving head frame 7 of theshaving head 6 at the one end and the support elements 46, 47 on thebottom of the housing 1 at the other end, the oscillation amplitude'svertical component exerted radially about the joints 21, 22 isrelatively small, so that a nearly linear motion of the shaving head 6in the directions of movement A and B can be assumed.

FIG. 4 shows a side view of the dry shaving apparatus of FIG. 3 with alongitudinal section through the housing 1, such that the joints 21, 23provided on the support arm 15 are visible. Parallel to the respectiveaxial directions of the pivot bearings provided, the joints 21, 23 havebearing trunnions and bearing bores, not shown, which are formed on abottom wall of the housing 1 and are provided on the end walls 33, 34 ofthe shaving head 6. Provided on the support elements 16, 17 is arespective support wall extending vertically to the shaving head 6 forpivotally connecting the electric drive mechanism 2 oscillatory about anaxis of oscillation 8 by means of the pivot bearings 12, 13 configuredas conical bearings.

The shaving head 6 carried by the support arms 14, 15—see FIG. 3—isconfigured, for example, as a twin shaving head whose cutting elements 5provided as outer cutters are shown symbolically by a broken line L. Itwill be understood that the design of the shaving head 6 is not limitedto the arrangement of one or two cutting elements 4, 5 within itsshaving head frame 7. Several cutter arrangements may well be providedin the shaving head frame 7 of the shaving head 6, and the associatedcutting elements may be of different configurations to suit a particularcutting function. For example, the possibility exists to provide in theoscillatory shaving head 6 two cutter arrangements operating asshort-hair cutters, and one cutter arrangement operating as long-hairtrimmer which is fitted therebetween.

FIG. 5 shows a sectional view of the housing 1 with an opening 52 in thewall of the housing 1 opposite the shaving head frame 7. The electricdrive mechanism 2 is secured to the shaving head frame 7 and is mountedon the support elements 16, 17 for oscillation about the axis ofoscillation 8 by means of at least one housing portion 20 having anorientation away from the shaving head frame 7 in the direction of thesupport elements 16, 17 provided in the housing 1—see FIG. 4. By meansof spring elements 9, 10 resting with one end against the housingportion 37 of the electric drive mechanism 2 and with their other endagainst inner wall portions of the housing 1, the electric drivemechanism 2 is in a mid-position when deactivated.

Provided inside the shaving head's 6 shaving head frame 7 adapted to beset in a reciprocating oscillation through the housing portion 20 whenthe electric drive mechanism 2 is started, is a shaving head frame 55which is mounted for pivotal motion about a pivot axis Z and includes atleast one cutter arrangement formed of cutting elements 4, 5, as well asan oscillatory bridge structure 25 for the transmission of a drivingmotion from a drive element 3 to the movable cutting element 4. Inaddition, in an area of the shaving head frame 7 remote from the cuttingelement 5, a further oscillatory bridge structure 50 is shown in brokenlines which operates on a further cutter arrangement suitable, forexample, for trimming contours. The oscillatory bridge structures 25 and50 are driven by the eccentric device 27 configured as a doubleeccentric device 44 which is affixed to the rotary drive element 3 ofthe electric drive mechanism 2.

FIG. 6 shows the housing 1 of a dry shaving apparatus with supportelements 16, 17 on which the electric drive mechanism 2 fixedly disposedin a bearing cage 35 is mounted for oscillation about an axis ofoscillation 8 by means of pivot bearings. The embodiment of FIG. 6 showsthe electric drive mechanism 2 in an oscillation position achievable inoperation in which the reciprocating shaving head 6 has reached a pointof reversal from the direction of movement B to the direction ofmovement A.

“The shaving head 6 is mounted on the support elements 16, 17 foroscillation in the directions of movement A and B through a supportingframe 40 and through support arms 14, 15 having joints 21, 22, 23, 24.The supporting frame 40 is of a U-shaped configuration and connectedthrough an engaging device 41 to a housing portion 20 of the bearingcage 35 for transmitting the oscillatory motion of the electric drivemechanism 2 about the axis of oscillation 8. The engaging device 41 iscomprised of a pin 43 engaging in a slot 42, said slot 42 being formedin the base part of the U-shaped supporting frame 40 and said pin 43being provided on the housing portion 20 of the bearing cage 35. Theelectric drive mechanism 2 comprises an electric motor having a driveelement 3 configured as a rotary shaft to which an eccentric device 27,configured as a double eccentric device, is secured in order to transmitthe driving motion from the drive element 3 to an oscillatory bridgestructure 25 provided in the shaving head frame 7 of the shaving head 6.The oscillatory bridge structure 25 has a slot of a dovetail-typeconfiguration in which the pin of the eccentric device 27 engages. Thedovetail-type configuration of the slot ensures a wear-free transmissionof the driving motion from the drive element 3 to the oscillatory bridgestructure 25 because the angles of the dovetail configuration are fittedto suit the positions of oscillation of the electric drive mechanism 2in operation.”

The U-shaped supporting frame 40 ensures an optimum oscillatory motionof the shaving head 6 in the directions of moves ment A and B inaddition to ensuring, through conically formed joints, a pivotal motionof the shaving head frame 7 with its one or more cutter arrangementsformed from cutting elements 4, 5 about the pivot axis Z.

Mounted on the bearing cage 35 of the electric drive mechanism 2 is anoscillatory bridge structure 50 illustrated by broken lines. Thisoscillatory bridge structure 50 may be utilized for operation of along-hair trimmer that may be fitted to an outside of the housing 1 orto an actuating switch, not shown. Similar to the oscillatory bridgestructure 25 in the shaving head 6, the oscillatory bridge structure 50may be utilized for attachment of an oscillating mass, not shown, forthe purpose of varying the respective oscillating masses and henceeffecting an amplitude variation.

What is claimed is:
 1. A dry shaving apparatus comprising: a housing; ashaving head comprising a shaving head frame and at least twocooperating cutting elements; an electric drive mechanism having a driveelement for transmitting reciprocating driving motion to at least one ofthe at least two cutting elements, wherein the electric drive mechanismis mounted for oscillation in the housing and which may be set inoscillation by operation of the dry shaving apparatus, and wherein theoscillatory motions of the electric drive mechanism are transmitted tothe shaving head to cause the shaving head to oscillate in a horizontaldirection to produce relative movement to a user's skin.
 2. The dryshaving apparatus as claimed in claim 1, wherein at least the shavinghead and the electric drive mechanism are flexibly mounted to be ablefor oscillation as an oscillating mass about a common axis ofoscillation during operation of the electric drive mechanism.
 3. The dryshaving apparatus as claimed in claim 2 wherein the oscillating masscomprises an interconnecting assembly attached at a first point to theoscillating mass of the electric drive mechanism and at a second pointto the shaving head, further comprising at least one of the shavinghead, a support arm, a bearing cage and an oscillatory bridge structure.4. The dry shaving apparatus as claimed in claim 2, wherein the axis ofoscillation is arranged to extend through a center of impact of theoscillating mass.
 5. The dry shaving apparatus as claimed in claim 4,wherein the axis of oscillation is arranged to extend at a distance tothe center of impact of the oscillating mass.
 6. The dry shavingapparatus as claimed in claim 2 wherein the electric drive mechanism ismounted for oscillation about the axis of oscillation with a pivotbearing.
 7. The dry shaving apparatus as claimed in claim 6, wherein thepivot bearing is provided on at least one support element of the housingand on a housing portion of the electric drive mechanism.
 8. The dryshaving apparatus as claimed in claim 7, further comprising a bearingcage wherein the housing portion of the electric drive mechanism issecured.
 9. The dry shaving apparatus as claimed in claim 7, wherein thepivot bearing is configured as a conical bearing.
 10. The dry shavingapparatus as claimed in claim 6, wherein the axis of oscillation isaligned in a direction transverse to the directions of movement of thecutting element.
 11. The dry shaving apparatus as claimed in claim 1,wherein the electric drive mechanism is mounted for oscillation about anaxis of oscillation.
 12. The dry shaving apparatus as claimed in claim 1wherein the shaving head is mounted for oscillation in the housing bymeans of an oscillating element.
 13. The dry shaving apparatus asclaimed in claim 12, wherein the oscillating element is formed by ahousing portion.
 14. The dry shaving apparatus as claimed in 5, whereinthe oscillating element comprises support arms having joints.
 15. Thedry shaving apparatus as claimed in claim 1 wherein the shaving head isdrivable by the oscillatory motions of the electric drive mechanism inthe directions of movement of the at least one of the cutting element.16. The dry shaving apparatus as claimed in claim 15, wherein theshaving head is driven by the electric drive mechanism so as tooscillate in opposition to the reciprocating movements of the at leastone of the cutting elements.
 17. The dry shaving apparatus as claimed inclaim 15, further comprising a weight removably attached to at least oneof the shaving head and the at least one of the cutting elements. toadjust the oscillation amplitudes.
 18. The dry shaving apparatus asclaimed in claim 17, wherein the oscillation amplitudes of at least oneof the shaving head and the at least one of the cutting elements arevariable.
 19. The dry shaving apparatus as claimed in claim 18, whereinthe oscillation amplitude of the shaving head is variable by varying theoscillating mass of at least one of the shaving head and the electricdrive mechanism.
 20. The dry shaving apparatus as claimed in claim 18,wherein the oscillating mass of at least one of the shaving head and theelectric drive mechanism is variable by the attachment of a balanceweight.
 21. The dry shaving apparatus as claimed in claim 18, whereinthe oscillation amplitudes are determinable by the at least one ofcutting elements, and the oscillation amplitude of the shaving head isadjustable thereto.
 22. The dry shaving apparatus as claimed in claim 1wherein the reciprocating travel of the shaving head in the directionsof movement is in a range from 0.05 mm to 1 mm.
 23. The dry shavingapparatus as claimed in claim 1, wherein the reciprocating travel of theshaving head is in a range from 0.15 mm to 0.5 mm.
 24. The dry shavingapparatus as claimed in claim 1, further comprising a support armconnected to the shaving head.
 25. The dry shaving apparatus as claimedin claim 24, wherein the support arm comprises at least two joints. 26.The dry shaving apparatus as claimed in claim 25 further comprising atleast one joint being configured as a film hinge.
 27. The dry shavingapparatus as claimed in claim 24 wherein the support arm is linked tothe electric drive mechanism through an oscillating element havingjoints.
 28. The dry shaving apparatus as claimed in claim 24, whereinthe support arm is linked through a first joint to at least one supportelement, and through a second joint to the shaving head frame of theshaving head, such as to be capable of oscillating in the directions ofmovement of the shaving head.
 29. The dry shaving apparatus as claimedin claim 24, further comprising a first joint for the support arm in thehousing at the end of the housing opposite the shaving head.
 30. The dryshaving apparatus as claimed in claim 24, wherein the support arm islinked for oscillation to at least one support element at a first pointand to a supporting frame carrying the shaving head at a second point.31. The dry shaving apparatus as claimed in claim 30, wherein thesupporting frame is linked to the electric drive mechanism.
 32. The dryshaving apparatus as claimed in claim 30 wherein the electric drivemechanism is linked to the supporting frame through a housing portion, abearing cage and an engaging device.
 33. The dry shaving apparatus asclaimed in claim 32, wherein the engaging device comprises a slot and apin engageable in the slot.
 34. The dry shaving apparatus as claimed inclaim 1 wherein the drive element of the electric drive mechanism islinked to a cutting element through an oscillatory bridge structure. 35.The dry shaving apparatus as claimed in claim 34 wherein the driveelement of the electric drive mechanism is linked to a first and asecond cutting element of different configurations through an eccentricdevice configured as a double eccentric device.
 36. The dry shavingapparatus as claimed in claim 1 wherein the drive element of theelectric drive mechanism is linked to a cutting element through at leastone eccentric device.
 37. The dry shaving apparatus as claimed in claim35, wherein an eccentric member of a double eccentric device is linkedto a cutting element of a long-hair trimmer through an oscillatorybridge structure.
 38. The dry shaving apparatus as claimed in claim 1wherein the electric drive mechanism comprises a direct-current motorhaving a drive element provided for rotation.
 39. The dry shavingapparatus as claimed in claim 1 wherein the electric drive mechanismcomprises a rocking armature motor having an oscillatory drive element.40. The dry shaving apparatus as claimed in claim 1 wherein the electricdrive mechanism and the shaving head are held in a mid-position by meansof at least one spring element.
 41. The dry shaving apparatus as claimedin claim 40, wherein the spring element bears with a first end againstthe electric drive mechanism and with a second end against the housing.